Bad weather last summer and a mild winter have combined to drive up costs at Casella Waste Systems Inc.'s landfills, which have increased expenditures to deal with leachate and landfill gas.

Excess water absorbed by the landfills from both Hurricane Irene and Tropical Storm Lee last year as well as mild weather this winter pushed landfill operation costs up by $1 million during the company's fiscal year third quarter that ended Jan 31. "The accumulated water absorbed by the landfills last summer has kept our leachate treatment costs well above normal, particularly the trucking of that leach...